AI 中文总结
针对多LEO卫星无小区OTFS上行链路的联合信道估计与数据检测问题，提出结构化双线性推理问题，开发低复杂度分层接收机，通过限制信道估计区域和无矩阵运算降低复杂度，仿真验证了接收机的信道估计精度和数据检测可靠性。
AI 中文摘要
由多颗低地球轨道（LEO）卫星组成的无小区网络为实现无处不在的连接提供了一种很有前景的架构，但其协同接收受到链路相关的残余延迟和多普勒频移的挑战。本文研究了多LEO卫星无小区正交时频空间（OTFS）上行链路的联合信道估计与数据检测（JCEDD）。将JCEDD问题表述为一个结构化双线性推理问题，涉及特定链路的稀疏波束 - 延迟 - 多普勒信道和多用户数据向量。开发了一种低复杂度分层JCEDD接收机，所有卫星先进行本地JCEDD，然后将其观测值和本地估计值在中心卫星处聚合进行协同优化。通过将信道估计限制在粗信息辅助的本地波束 - 延迟 - 多普勒区域并以无矩阵方式评估所需的前向和伴随运算来降低计算复杂度。仿真结果验证了所提JCEDD接收机的信道估计精度和数据检测可靠性。
英文摘要
Cell-free networks formed by multiple low Earth orbit (LEO) satellites offer a promising architecture for ubiquitous connectivity, but their cooperative reception is challenged by link-dependent residual delays and Doppler shifts. This paper investigates joint channel estimation and data detection (JCEDD) for multi-LEO-satellite cell-free orthogonal time frequency space (OTFS) uplinks. The JCEDD problem is formulated as a structured bilinear inference problem involving link-specific sparse beam--delay--Doppler channels and a multiuser data vector. We develop a low-complexity hierarchical JCEDD receiver in which all satellites first perform local JCEDD, and their observations and local estimates are then aggregated at a central satellite for cooperative refinement. Computational complexity is reduced by restricting channel estimation to coarse-information-aided local beam--delay--Doppler regions and evaluating the required forward and adjoint operations in a matrix-free manner. Simulation results validate the channel-estimation accuracy and data-detection reliability of the proposed JCEDD receiver.
